Re: two mysteries

[Ray Andrews <rayandrews@eastlink.ca>]

On 11/07/2015 01:55 AM, Bart Schaefer wrote:
> My only guess is that in some cases the assignment occurs before the
> declaration:
>
> torch% START_IDX=1+((idx-1)/page_hight)*page_hight
> torch% print ${(t)START_IDX}
> scalar
> torch% integer START_IDX
> zsh: division by zero
> torch% print ${(t)START_IDX}
> integer
> torch%
>
> The value currently in the scalar $START_IDX is evaluated when the type
> changes to integer, which causes the division by zero.
>
I think you bagged it.  The type is changed *even* when the assignment 
fails, that didn't even occur to me.  And yes, the logic is sound--it 
*has* to be an integer for 'division by zero' to be a relevant message.  
I think where I went off the rails is that this was part of  my trying 
to pass arrays (as we discussed) rather than flocks of independent 
values, and whereas I had at one time:

     integer page_hight

this became:

     files[page_hight]

... and (so far) I don't know how to typeset an element of an array so 
it was a bloody scalar and became an integer even when it failed to be 
assigned--so tweedle-dum was in fact tweedle-dee and I had the right 
issue but the bassackwards interpretation. And, as the clouds part, I 
now think I know how I fixed it:

     files[page_hight]=$files_frame[page_hight]

     files[page_hight]=$(( files_frame[page_hight] ))

... because when I forced it to be integer all the arithmetic ducks 
lined up ... or something very much like that.  It's actually a long 
chain of arithmetics, but I'll be primed for this next time something 
like that happens.  I'm hunting ducks holding my shotgun backwards.  
Geez, I wish we had in inviolable integer.

} Didn't I read that
} there's a difference between 'typeset -i' and 'integer'?

Read where ...?  Doc:

I dunno, I just vaguely recall something, thought I'd ask. Something in 1st Peter, I think--some subtlety ... nevermind.

Masterful, Sensei.